HONG Kong says the US government got National Security Agency leaker Edward Snowden's middle name wrong in documents it submitted seeking his arrest.

Mr Snowden hid in Hong Kong for several weeks after revealing secret US surveillance programs. Hong Kong allowed him to fly to Moscow on Sunday, saying a US request for his arrest did not fully comply with its requirements.

Justice Secretary Rimsky Yuen said on Tuesday that discrepancies in the paperwork filed by US authorities were to blame.

He said Hong Kong immigration records listed Mr Snowden's middle name as Joseph, but the US government used the name James in some documents and referred to him only as Edward J. Snowden in others.

"These three names are not exactly the same, therefore we believed that there was a need to clarify," he said.

Mr Yuen said US authorities also did not provide Mr Snowden's passport number.

The decision to let Mr Snowden leave Hong Kong irked the White House, which said it damaged US-Chinese relations.

US officials implied that Beijing had a hand in letting Mr Snowden leave Hong Kong, a former British colony that is now a semiautonomous region with its own legal system.

Hong Kong officials have pushed back, stressing that they followed the city's rule of law in processing the US request.

Mr Yuen said the confusion over Mr Snowden's identification and his passport were among factors that delayed an arrest. He said the government requested clarification from its counterparts in the US on Friday afternoon.

"Up until the minute of Snowden's departure, the very minute, the US Department of Justice did not reply to our request for further information. Therefore, in our legal system, there is no legal basis for the requested provisional arrest warrant," Mr Yuen said. In the absence of such a warrant, the "Hong Kong government has no legal basis for restricting or prohibiting Snowden leaving Hong Kong."

Mr Snowden flew from Hong Kong to Moscow and was expected to seek asylum in Ecuador.